The Pre-Columbian Goldwork
Pre-Columbian Cultures are recognized worldwide by their magnificent gold work. Their skilled talent set them apart from other contemporary cultures. They developed the skills to work with gold, an extremely fragile surface, as well as platinum, through the mastering of the Lost Wax Method technique and the use of alloys.
What is Tumbaga?
Pre-Columbian Goldsmiths discovered a metallurgical method known as Tumbaga, which allowed them to work gold to make jewelry and ornaments.
Respectively Gold and Cooper melt at 1,063°C and 1,083°C, temperatures too high to work with manually. Pre-Columbian Goldsmiths, however, realized that if they melted these two metals together the fusion temperature would drop to 850°C.The result of this fusion is a malleable alloy that goldsmiths hammered into thin sheets suitable for carving. They used the alloys along with the Lost Wax Method to create volumetric figures. The cooper visible on the outside of the sheet was easily removed with citric acid found in natural elements such as fruits.
The picture below depicts a ornament displayed in the Gold Museum that was elaborated with Tumbaga alloy. Some cooper residues can be still seen on the surface.
A good example of what the artisans were able to do with the Tumbaga alloy is the Snail Shell masterpiece displayed in the Gold Museum in Bogota. The snail shell was originally wrapped with this alloy. As the time passed the natural carcass vanished and what is seen today is the gold with the snail shell layout.
Source for the above picture: Gold Museum Web Site - October 2012.
What is Lost Wax Technique?
Artisans and Goldsmiths designed Pre-Columbian jewelry and utilitarian pieces by first shaping the desired figures out of beehive wax. Once the desired shape and design were incorporated onto the solid wax figurine, it would be covered with clay, leaving a small orifice communicating the exterior through the clay to the wax chamber.
The clay was left to dry and then heated. The wax would melt and was removed through the orifice. A pipe was then used to pour the Tumbaga mixture into the clay. The clay is left to cool and then broken. A solid Tumbaga piece with the shape of the original wax figure is recovered from the inside with two identifiable layers: the cooper on the exterior and the gold in the interior. With a citric acid, from natural fruits, the layer of cooper is removed allowing the gilded figure to surface. It was then manually polished to give the gilded look. Variations on the technique allowed Goldsmiths and artisans to design containers such as Poporos, used to carry the mineral lime used while chewing coca